//  This file is part of YamlDotNet - A .NET library for YAML.
//  Copyright (c) Antoine Aubry and contributors

//  Permission is hereby granted, free of charge, to any person obtaining a copy of
//  this software and associated documentation files (the "Software"), to deal in
//  the Software without restriction, including without limitation the rights to
//  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
//  of the Software, and to permit persons to whom the Software is furnished to do
//  so, subject to the following conditions:

//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.

//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.

using System.Collections.Generic;
using System.Globalization;
using YamlDotNet.Core;

namespace YamlDotNet.Serialization.Utilities
{
    internal sealed class ObjectAnchorCollection
    {
        private readonly IDictionary<string, object> objectsByAnchor = new Dictionary<string, object>();
        private readonly IDictionary<object, string> anchorsByObject = new Dictionary<object, string>();

        /// <summary>
        /// Adds the specified anchor.
        /// </summary>
        /// <param name="anchor">The anchor.</param>
        /// <param name="object">The @object.</param>
        public void Add(string anchor, object @object)
        {
            objectsByAnchor.Add(anchor, @object);
            if (@object != null)
            {
                anchorsByObject.Add(@object, anchor);
            }
        }

        /// <summary>
        /// Gets the anchor for the specified object.
        /// </summary>
        /// <param name="object">The object.</param>
        /// <param name="anchor">The anchor.</param>
        /// <returns></returns>
        public bool TryGetAnchor(object @object, out string anchor)
        {
            return anchorsByObject.TryGetValue(@object, out anchor);
        }

        /// <summary>
        /// Gets the <see cref="System.Object"/> with the specified anchor.
        /// </summary>
        /// <value></value>
        public object this[string anchor]
        {
            get
            {
                object value;
                if (objectsByAnchor.TryGetValue(anchor, out value))
                {
                    return value;
                }

                throw new AnchorNotFoundException(string.Format(CultureInfo.InvariantCulture, "The anchor '{0}' does not exists", anchor));
            }
        }
    }
}